Dental impression-tray.



No. 699,776. Patenfed May l3, I902.

E. L. TOWNSEND. DENTAL IMPRESSION TRAY.

(Application filed July 29, 1901.)

(No Model.)

BY /-//5 HTTUFF/VE'YS mun ATENT QFFICE.

DENTAL lIVIPRESSION -TRAY.

SPECIFICATION forming part of Letters Patent No. 699,776, dated May 13, 1902.

Application filed July 29, 1901. Serial No. 70,162. (No model.)

To (tZZ whom ntrty concern.-

Be it known that I, EMORY L. TOWNSEND, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles, State of California, have invented new and useful Improvements in Impression-Trays, of which the following is a specification.

My improvement relates to trays for holding the material by means of which impressions are taken for use in making artificial teeth; and the object thereof is to provide a tray by means of which the impressed material can be removed from the mouth in sections without any danger of destroying or defacing the impression. I accomplish this object by means of the tray described herein, and illustrated in the accompanying drawings, in which Figure 1 is a plan of my improved tray adapted for taking impressions of the upper part of the mouth. Fig. 2 is a plan of a partial tray for taking impressions of a portion of the jaw and having impressed material therein. Fig. 3 is a cross-section on the line 3 3 of Fig. 2.

In the practice of dentistry the common and almost universal material with which impressions are taken for use in making artificial teeth is plaster-of-paris, which sets very quickly and is rather brittle when set. The trays in common use are cup-shaped to hold the material to be impressed, and when the material held therein is impressed by the teeth and jaw to be fitted and the material has set it is necessary to remove this impressed material from the mouth. As the teeth are always smaller at the neck than at the crown and the plaster-of-paris sets closely to the neck, in removing the same it is often broken, often into many small pieces, which it is impossible to put together with any degree of accuracy. It is to obviate these irregular and numerous fractures of the plaster-ofparis that my invention is designed.

In the drawings, A is an impression-tray constructed of the usual material and of the usual shape. I provide said tray with a lining B, which is divided into sections adapted to fit one against the other and having upturned edges B where said sections touch each other. These upturned edges extend upward far enough into the impressed material C so that the same may be easily broken on a line between the Various sections. These various sections are so formed that the contacting upturned edges form a line along the center of the teeth in the jaw and at other-points runnin g to the edges of the material, so that when the material breaks on these lines each section can be removed separately from the mouth, and thereby produce a cast in sections that can be easily, correctly, and quickly put together.

In the operation of my device before the sections of the lining are put into the tray they are coated on the surface which is to be presented to the impression material with some substance which will or can be easily caused to separate from the impression material. They are then placed in the tray and the impression material is poured therein and the impression is then taken. As soon as the impressed material has set, the trayis removed,leaving the sectional lining exposed, and the impression material is easily broken on the lines between the different sections of the lining, when each section can be removed entire.

In Fig. 2 I have shown a partial tray filled with impressed material, with a line through the center to show the breaking-line. In Fig. 3 I have shown a cross-section thereof to show how the upturned edges of the lining cause the impressed material to break on the line between the sections.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. A lining for impression-trays composed of detached sections extending transversely to a line which coincides with the central tooth-line when the tray is used in taking an impression.

2. The herein-described detached lining for impression-trays, comprising a plurality of sections which meet longitudinally on a line which coincides with the central tooth-line when the tray is used in taking an impression said sections having upturned edges along their meeting-lines, substantially as described herein.

In witness that I claim the foregoing I have hereunto subscribed my name this 22d day of July, 1901.

EMORY L. TOWNSEND..- Witnesses:

G. E. HARPHAM, MATTIE MOGINNIS. 

